Control of the Particle Distribution in Inkjet Printing through an Evaporation-Driven Sol–Gel Transition

Abstract

2014) 'Control of the particle distribution in inkjet printing through an evaporation-driven sol-gel transition.', ACS applied materials interfaces., 6 (12). pp. 9572-9583.Further information on publisher's website:http://dx.doi.org/10.1021/am501966nPublisher's copyright statement:This document is the Accepted Manuscript version of a Published Work that appeared in nal form in ACS Applied Materials Interfaces, copyright c American Chemical Society after peer review and technical editing by the publisher. To access the nal edited and published work see http://dx.doi.org/10.1021/am501966n. Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Abstract A ring stain is often an undesirable consequence of a droplet drying. Particles inside evaporating droplets with a pinned contact line are transported towards the periphery by radial flow. In this paper, we demonstrate how suspensions of laponite can be used to control the radial flow inside picolitre droplets and produce uniform deposits.The improvement in homogeneity arises from a sol-gel transition during evaporation.Droplets gel from the contact line inwards, reducing radial motion of particles and thus inhibiting the formation of a ring stain. The internal flows and propagation of the gelling front were followed by high-speed imaging of tracer particles during the evaporation of picolitre droplets of water. In the inkjet nozzle, the laponite network * To whom correspondence should be addressed † Department of Chemistry, Durham University, Durham, DH1 3LE, United Kingdom ‡ School of Engineering and Computing Sciences, Durham University, Durham, DH1 3LE, United Kingdom 1 is broken down under high shear. Recovery of the low shear viscosity of laponite suspensions was shown to be fast with respect to the lifetime of the droplet, which was instrumental in controlling the deposit morphology. The radial and vertical particle distributions within dried deposits were measured for water droplets loaded with 1%w and 5%w polystyrene spheres and various concentrations of laponite. Aggregation of the polystyrene spheres was suppressed by addition of colloidal silica. The formulation can be tuned to vary the deposit profile from a ring to a pancake or a dome.

Rheological study on 3D printability of alginate hydrogel and effect of graphene oxide

“…A material is said to be thixotropic when its apparent viscosity decreases with time under a constant shear rate. As for thixotropic materials, the bestknown example is the thixotropic paints and the other examples include concentrated suspensions, drilling fluids, emulsions, protein solutions, laponite, and silk nanofibril-based hydrogel [23][24][25][26] . The 3D printing head consists of a piston, a syringe, and a nozzle.…”

Analysis of the effects of evaporative cooling on the evaporation of liquid droplets using a combined field approach

“…For example, a sessile droplet often leaves the solute particles on the substrate on which it rested, resulting in different patterns of deposition upon drying12345678. This phenomenon has been used as the basis of many applications including DNA-RNA mapping910, ink-jet printing of functional materials111213, and fabrication of colloidal photonic crystals14. In these applications, controlling the distribution of the particle deposition after the liquid has dried is vital.…”

Corrigendum: N‐Oxide 1,2,4,5‐Tetrazine‐Based High‐Performance Energetic Materials

“…Talbot et al quantitatively investigated the effect of viscoelastic properties of aqueous suspensions of polystyrene particles and laponite, a disc‐shaped nanoparticle, on the deposit morphologies after the drying of inkjet‐deposited droplets 16. Laponite was introduced to induce a sol–gel transition in the drying drops, which transforms the liquid from an initially stable colloidal dispersion to a soft gel.…”

“…Given that evaporation‐driven flow toward the pinned contact line is always present in a volatile sessile drop, the vast majority of these approaches was based on affecting the hydrodynamics of drying drops. Different additives, including surfactants,10, 14 polymers,15 cosolvents2 and nanoparticles,16 were introduced to manipulate the flow patterns in evaporating drops. External methods that require no additives, such as electrowetting17 and exposure of the drying drops to vapours of miscible, low‐surface‐tension liquids,18 have also been successfully utilised.…”